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Re: Tube identificaion help (833)

Tesla List wrote:
> 
> Original Poster: David Trimmell <davidt-at-pond-dot-net>
> 
> Hello, I know there are several folks on this list who have used 833
> transmitter tubes in Tube coils. I have two 833's that came from a local
> radio station, and on the boxes they had marked "833-A", but these tubes
> have a thick plate, aprox 1/4". The plate is unlike the standard
> "sheet-metal" variety, it is a light grey-silver, almost like pewter in
> color and is somewhat rough on the surface, with close inspection. The
> overall construction quality is significantly superior to the Amprex 833A I
> have. The light grey color of the plates seems to light in color for
> graphite, but these tubes do run very cool in comparison to the Amprex. No
> markings on the envelope, but there is a serial number on the ceramic
> insulator at the base of the plate.
> 
> Any Ideas guys?
> 
> I understand that there is a 833-A, 833-C and a 833-D, what are the
> characteristics of these? I have the data-sheets on the 833-A, but cannot
> find any info on the other varieties. Appreciate any help!
> 
> Regards,
> 
> David Trimmell

David,

It sounds like you have gotten your hands on a pair of 833C's which have
a carbon/graphite plate and will take a great deal more abuse in Tesla
coil use than will the standard metal plate 833A's. Nice find! You now
have two perfect reasons to start on that tube coil!

My vacuum tube coil uses a pair of 833C's and produces approximately 24
inches of spark with an input of almost 7 KW.... VTC's are very
inefficient. Even at this power level the plates on the 833C's will
barely glow red after continuous runs of 2 minutes or more. Just a
single 833C on this coil will produce 20" of spark with the plate
glowing a dull red. The limiting factor of this coil with both tubes
connected is the physical size and spacing of the primary/secondary....a
condition which I have not taken the time to rectify yet.

As far as specs go, RF Parts has specs on the 833C's and others in their
catalogue. Their online catalogue can be found at:

http://www.rfparts-dot-com/

The ratings on my 833C's are: Plate Diss  450
                              Plate Volts 4000
			      Ic  MA      500
                              P in/ watts 1800

Of course, name plate ratings are only a starting point for Tesla
coilers! :^)
	
While on the subject of URL's, it might be worthy to note that if
someone puts a URL in their post and includes the "http://" in front of
the URL that most browsers will link directly to the URL by simply
clicking on the address, which saves folks the hassle of having to
retype the whole address or copy and paste and then add the "http://".
Thank you for your support!

Happy VT coiling,

Ed Wingate RATCB